I use Dunlop Pearloid Mediums and Heavys and I have to say I've never worn a pick out before I lost it! Also, I tried once to see if I could wear one out sawing on Ernie Ball .11-.52s all my might picking sharply on downward angles for more than an hour to the point where I broke the B string yet the pick didn't have a single scratch on it that I could see.
To boot, my tone was harsh as an ice pick from picking so hard. If someone is wearing out heavy picks that fast, I sure as shit wouldn't want to be sitting in front of their speakers for long!